Objectives: Study the mechanisms of latent murine cytomegalovirus infection in the salivary glands and lymphoid tissue of mice chronically infected with this virus and determine effect of chronic infection on lymphoma development. Major Findings: The mouse cytomegalovirus causes chronic infection in the submaxillary glands, lymph nodes, and spleens of many strains of mice. Infection in the lymph nodes and spleen probably occurs in lymphocytes. The murine cytomegalovirus belongs to the herpesvirus group of animal viruses, along with the Epstein-Barr virus and Herpesvirus saimiri. Proposed Course: This work is completed. Results indicate that chronic CMV infection does not enhance or accelerate natural development of lymphoma in mice.